The advantages of Docker, the difference with virtual machine technology, three important concepts, architecture and working principle explained in detail
With the development of cloud computing and containerization technology, Docker, as a lightweight containerization technology, has received more and more attention and application. This article will introduce in detail the advantages of Docker, the difference from virtual machine technology, three important concepts, architecture and working principle.
1. What is Docker
Docker is a lightweight containerization technology that packages an application and its dependencies into a portable container, enabling rapid deployment, portability, and scalability. Docker containers can run on any platform that supports Docker, including physical machines, virtual machines, public clouds, and private clouds.
2. What are the advantages of Docker
1. Lightweight: Compared with traditional virtual machines, Docker containers are lighter, start faster, and occupy less resources.
2. Portability: Docker containers can run on any platform that supports Docker, without worrying about compatibility issues caused by environmental differences.
3. Fast deployment: Docker containers can be deployed quickly, and it only takes a few seconds to start a new container.
4. Simplified configuration: Docker containers can be built through images, which contain applications and their dependencies, which can avoid cumbersome configuration.
5. Scalability: Docker containers can be rapidly expanded, and the number of containers can be dynamically increased or decreased as needed, thereby achieving high availability and load balancing.
3. The role of Docker
The main role of Docker is to package an application and its dependencies into a portable container, enabling rapid deployment, portability, and scalability. Docker containers can run on any platform that supports Docker, including physical machines, virtual machines, public clouds, and private clouds.
4. Docker stands out
The reason why Docker can stand out is mainly because it has the following advantages:
1. Lightweight: Compared with traditional virtual machines, Docker containers are lighter, start faster, and occupy less resources.
2. Portability: Docker containers can run on any platform that supports Docker, without worrying about compatibility issues caused by environmental differences.
3. Fast deployment: Docker containers can be deployed quickly, and it only takes a few seconds to start a new container.
4. Simplified configuration: Docker containers can be built through images, which contain applications and their dependencies, which can avoid cumbersome configuration.
5. Scalability: Docker containers can be rapidly expanded, and the number of containers can be dynamically increased or decreased as needed, thereby achieving high availability and load balancing.
Five, the difference between Docker and virtual machine technology
Docker is very different from traditional virtual machine technology, mainly in the following aspects:
1. Architecture: The Docker container runs based on the operating system kernel of the host machine, while the virtual machine uses virtualization technology to simulate the hardware environment and run a complete operating system.
2. Resource occupation: Compared with virtual machines, Docker containers occupy fewer resources and start faster.
3. Portability: Docker containers can run on any platform that supports Docker without worrying about compatibility issues caused by environmental differences, while virtual machines need to install different virtualization software on different platforms.
4. Deployment method: Docker containers can be built through images, which contain applications and their dependencies, which can avoid cumbersome configuration, while virtual machines need to install operating systems and applications.
6. Summary of the difference between Docker container and virtual machine
The difference between a Docker container and a virtual machine is mainly reflected in the following aspects:
1. Architecture: The Docker container runs based on the operating system kernel of the host machine, while the virtual machine uses virtualization technology to simulate the hardware environment and run a complete operating system.
2. Resource occupation: Compared with virtual machines, Docker containers occupy fewer resources and start faster.
3. Portability: Docker containers can run on any platform that supports Docker without worrying about compatibility issues caused by environmental differences, while virtual machines need to install different virtualization software on different platforms.
4. Deployment method: Docker containers can be built through images, which contain applications and their dependencies, which can avoid cumbersome configuration, while virtual machines need to install operating systems and applications.
Seven, three important concepts in Docker
1. Image (mirror) a special file system
A Docker image is a special file system that contains an application and its dependencies. Images can be built using a Dockerfile, which is a text file that contains instructions for building an image.
2. Container (container) entity of image runtime
A Docker container is an entity of image runtime, which can be understood as a lightweight virtual machine. Containers can be created by mirroring, which contains applications and their dependencies, and can run applications directly.
3. Repository (warehousing) is the place where mirror files are stored centrally
Docker storage is a place where image files are stored centrally, and images can be uploaded to the storage for other users to download and use. Docker Hub is a public Docker repository that is free to use.
8. Docker architecture and working principle
The Docker architecture mainly includes a Docker client, a Docker daemon, a Docker image, and a Docker container.
The Docker client is a tool for users to interact with Docker, and can operate Docker through the command line or API.
The Docker daemon is the core component of Docker, responsible for managing Docker images and containers, and communicating with Docker clients.
A Docker image is a special file system that contains an application and its dependencies, which can be built with a Dockerfile.
A Docker container is an entity of mirroring runtime, which can be understood as a lightweight virtual machine, which can be created through mirroring. The container contains applications and their dependencies, and can run applications directly.
The working principle of Docker mainly includes the following steps:
1. Build a mirror image: Build a mirror image through a Dockerfile, which contains instructions for building a mirror image.
2. Upload image: upload the image to the Docker repository, so that other users can download and use it conveniently.
3. Create a container: Create a container through a mirror, which contains the application and its dependencies, and can run the application directly.
4. Start the container: Once the container is started, the application can run in the container.
5. Monitoring container: You can monitor the running status of the container through the Docker client, including the container's log, CPU and memory usage, etc.